A large majority of the commercially available dental porcelains contain uranium, a radioactive element. The uranium is present in dental porcelain in order to simulate natural tooth fluorescence. Recent studies indicate that the radiation dose to the oral mucosa from the uranium in dental porcelain may be excessive. In addition, investigations in this laboratory of the fluorescence from dental porcelain containing uranium show that, in general, the emission often does not compare favorably with that from natural teeth. The objective of this investigation is to seek suitable non-radioactive luminophors for incorporation into dental porcelain which simulate natural tooth fluorescence and which can withstand the high temperatures necessary for fusing and firing the ceramics. All luminescing materials will be observed with respect to their emission characteristics in a spectrofluorometer modified so that corrected spectra can be obtained. Precise quantum efficiencies will be measured and compared with those noted for natural tooth structures. After compounds are found that have a similar fluorescence to natural teeth, they will be used to construct representative porcelain specimens. These specimens will be prepared from porcelain base material and fired in the usual manner for making porcelain teeth. The fluorescence spectra of the porcelain specimens will then be obtained and compared with the results for the agents themselves for any change in band shape and position. The porcelain specimens will also be tested for their toxicity and stability to the oral environment.